Re: FAIL: gcc.c-torture/execute/950628-1.c execution, -O1

["John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>]

> typedef struct
> {
>   char hours, day, month;
>   short year;
> } T;
> 
> T g (void)
> {
>   T now;
> 
>   now.hours = 1;
>   now.day = 2;
>   now.month = 3;
>   now.year = 4;
>   return now;
> }

> (insn 22 20 23 (set (reg:HI 98)
>         (const_int 4 [0x4])) 91 {*pa.md:2554} (nil)
>     (expr_list:REG_EQUAL (const_int 4 [0x4])
>         (nil)))
> 
> (insn 23 22 24 (set (mem/s:HI (plus:SI (reg/f:SI 3 %r3)
>                 (const_int 12 [0xc])) 0)
>         (reg:HI 98)) 91 {*pa.md:2554} (nil)
>     (nil))

It appears that insn 23 is marked dead at line 4288 in flow.c:

	      if (rtx_equal_p (mem, r))
                return 1;

The rtx's mem and r are equal.  Here is the debug trace:

(gdb) bt
#0  0x1b613c in insn_dead_p (pbi=0x61, x=0x7ae8dd00, call_ok=62,
    notes=0x7ae8d570) at ../../gcc/flow.c:4287
#1  0x1b53f0 in propagate_one_insn (pbi=0x4009aa78, insn=0x7ae93660)
    at ../../gcc/flow.c:3767
#2  0x1b5db4 in propagate_block (bb=0x40097da8, live=0x7ae93660,
    local_set=0x0, cond_local_set=0x0, flags=16) at ../../gcc/flow.c:4201
#3  0x1b472c in calculate_global_regs_live (blocks_in=0x400339a0,
    blocks_out=0x0, flags=16) at ../../gcc/flow.c:3587
#4  0x1b3b4c in update_life_info (blocks=0x0, extent=UPDATE_LIFE_GLOBAL,
    prop_flags=63) at ../../gcc/flow.c:3075
#5  0x1bdf30 in life_analysis (f=0x7ae933a0, file=0x0, flags=63)
    at ../../gcc/flow.c:2937
#6  0xa0064 in rest_of_compilation (decl=0x7ae80820) at ../../gcc/toplev.c:3269
#7  0x57530 in c_expand_body (fndecl=0x7ae80820, nested_p=0)
    at ../../gcc/c-decl.c:6705
#8  0x5711c in finish_function (nested=0) at ../../gcc/c-decl.c:6626
#9  0x3dd7c in yyparse_1 () at /usr/local/share/bison.simple:323
#10 0x45af8 in yyparse () at ../../gcc/c-lex.c:157
#11 0x9e220 in compile_file (name=0x190 <Address 0x190 out of bounds>)
    at ../../gcc/toplev.c:2379
#12 0xa3b5c in main (argc=0, argv=0x40001728) at ../../gcc/toplev.c:4879
#13 0x7af1e6cc in ?? () from /usr/lib/libc.1

Richard, you looked at this code fairly recently.  Got any clues?

Dave
-- 
J. David Anglin                                  dave.anglin@nrc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6605)